In general, a cutting tool is used to typically cut a ferrous or non-ferrous metal, or non-metallic material, which is installed to a machine tool for performing a cutting operation in order to make a workpiece in a desired shape. A cutting method using the cutting tool generally includes a turning work in which a fixed cutting tool cuts a rotating workpiece and a milling work in which the cutting tool rotates to cut the fixed workpiece. In the turning work, a cutting insert is mounted on the seat portion of a cutting tool body, i.e., a cutter body, which performs an inner diameter portion cutting, an outer diameter portion cutting, contouring or the like. In contrast, in the milling work, a cutting insert is mounted on the insert seat portion of a cutter body to perform a planar cutting, a lateral cutting, a groove cutting, an inclination cutting, a curved surface cutting or the like.
The milling work as mentioned above, wherein the cutting tool rotates to cut the fixed workpiece, conventionally employs an one-sided type cutting insert in which a cutting edge is typically provided only on the upper surface in order to prevent interference between the cutting tool and the workpiece and further to ensure even sharper cutting blade. However, various studies have been made to resolve the drawbacks retained in the one-sided type cutting insert.
The U.S. Pat. Nos. 6,196,771 and 6,200,072, European Patent No. 1,468,770 and United States Patent Application Publication No. 2004/208,714 disclose the cutting tools developed for such purposes.
The cutting insert to be mounted on the cutter body of the milling machine, which is disclosed in the U.S. Pat. No. 6,196,771 or 6,200,072, has drawbacks in that since a chip is discharged along the surface of the upper or lower surface during the cutting operation, it is not regarded as an optimal method to address a molten deposition or adherence of the chip on the upper or lower surface, and further is not capable of improving the roughness of the machined surface.
In order to solve the above drawbacks, the applicant of this invention filed and acquired the Korean Patent No. 698,383. This patent is provided with a cutting insert formed with cutting edge portions on the opposite sides thereof and a cutter body formed with one or more insert seats with which the cutting insert is easily coupled, such that it can prolong the life span of the cutting insert and the cutter body, improve the roughness of the machined surface, and maximize the cutting efficiency.
In this regard, the present invention is designed to perform a further study on the cutting insert and the cutting tool for milling works in which the chip is to be cut in a short form in case of high depth of cutting, thereby reducing the friction and the cutting resistance as well as increasing the productivity of the cutting works therethrough.